/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/*****************************************************************************
 *  kernel/group/group_create.c
 *
 *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 *****************************************************************************/

/*****************************************************************************
 * Included Files
 *****************************************************************************/

#include <tinyara/config.h>

#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#if defined(CONFIG_PREFERENCE) && CONFIG_TASK_NAME_SIZE > 0
#include <string.h>
#endif

#include <tinyara/kmalloc.h>

#include "environ/environ.h"
#include "group/group.h"

#ifdef HAVE_TASK_GROUP

/*****************************************************************************
 * Pre-processor Definitions
 *****************************************************************************/
/* Is this worth making a configuration option? */

#define GROUP_INITIAL_MEMBERS 4

/*****************************************************************************
 * Private Types
 *****************************************************************************/

/*****************************************************************************
 * Private Data
 *****************************************************************************/
/* This is counter that is used to generate unique task group IDs */

#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
static gid_t g_gidcounter;
#endif

/*****************************************************************************
 * Public Data
 *****************************************************************************/

#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
/* This is the head of a list of all group members */

FAR struct task_group_s *g_grouphead;
#endif

/*****************************************************************************
 * Private Functions
 *****************************************************************************/

/*****************************************************************************
 * Name: group_assigngid
 *
 * Description:
 *   Create a unique group ID.
 *
 * Parameters:
 *   tcb - The tcb in need of the task group.
 *
 * Return Value:
 *   None
 *
 * Assumptions:
 *   Called during task creation in a safe context.  No special precautions
 *   are required here.
 *
 *****************************************************************************/

#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
static void group_assigngid(FAR struct task_group_s *group)
{
	irqstate_t flags;
	gid_t gid;

	/* Pre-emption should already be enabled, but lets be paranoid careful */

	sched_lock();

	/* Loop until we create a unique ID */

	for (;;) {
		/* Increment the ID counter.  This is global data so be extra paranoid. */

		flags = enter_critical_section();
		gid = ++g_gidcounter;

		/* Check for overflow */

		if (gid <= 0) {
			g_gidcounter = 1;
			leave_critical_section(flags);
		} else {
			/* Does a task group with this ID already exist? */

			leave_critical_section(flags);
			if (group_findbygid(gid) == NULL) {
				/* Now assign this ID to the group and return */

				group->tg_gid = gid;
				sched_unlock();
				return;
			}
		}
	}
}
#endif							/* HAVE_GROUP_MEMBERS */

/*****************************************************************************
 * Public Functions
 *****************************************************************************/

/*****************************************************************************
 * Name: group_allocate
 *
 * Description:
 *   Create and a new task group structure for the specified TCB. This
 *   function is called as part of the task creation sequence.  The structure
 *   allocated and zeroed, but otherwise uninitialized.  The full creation
 *   of the group of a two step process:  (1) First, this function allocates
 *   group structure early in the task creation sequence in order to provide a
 *   group container, then (2) group_initialize() is called to set up the
 *   group membership.
 *
 * Parameters:
 *   tcb   - The tcb in need of the task group.
 *   ttype - Type of the thread that is the parent of the group
 *
 * Return Value:
 *   0 (OK) on success; a negated errno value on failure.
 *
 * Assumptions:
 *   Called during task creation in a safe context.  No special precautions
 *   are required here.
 *
 *****************************************************************************/

int group_allocate(FAR struct task_tcb_s *tcb, uint8_t ttype)
{
	FAR struct task_group_s *group;
	int ret;

	DEBUGASSERT(tcb && !tcb->cmn.group);

	/* Allocate the group structure and assign it to the TCB */

	group = (FAR struct task_group_s *)kmm_zalloc(sizeof(struct task_group_s));
	if (!group) {
		return -ENOMEM;
	}
#if CONFIG_NFILE_STREAMS > 0 && (defined(CONFIG_BUILD_PROTECTED) || \
	defined(CONFIG_BUILD_KERNEL)) && defined(CONFIG_MM_KERNEL_HEAP)
	/* If this group is being created for a privileged thread, then all elements
	 * of the group must be created for privileged access.
	 */

	if ((ttype & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_KERNEL) {
		group->tg_flags |= GROUP_FLAG_PRIVILEGED;
	}

	/* In a flat, single-heap build.  The stream list is allocated with the
	 * group structure.  But in a kernel build with a kernel allocator, it
	 * must be separately allocated using a user-space allocator.
	 */

	group->tg_streamlist = (FAR struct streamlist *)group_zalloc(group, sizeof(struct streamlist));

	if (!group->tg_streamlist) {
		kmm_free(group);
		return -ENOMEM;
	}
#endif

	/* Attach the group to the TCB */

	tcb->cmn.group = group;

#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
	/* Assign the group a unique ID.  If g_gidcounter were to wrap before we
	 * finish with task creation, that would be a problem.
	 */

	group_assigngid(group);
#endif

	/* Duplicate the parent tasks environment */

	ret = env_dup(group);
	if (ret < 0) {
#if CONFIG_NFILE_STREAMS > 0 && (defined(CONFIG_BUILD_PROTECTED) || \
	defined(CONFIG_BUILD_KERNEL)) && defined(CONFIG_MM_KERNEL_HEAP)
		group_free(group, group->tg_streamlist);
#endif
		kmm_free(group);
		tcb->cmn.group = NULL;
		return ret;
	}

	/* Initialize the pthread join semaphore */

#ifndef CONFIG_DISABLE_PTHREAD
	(void)sem_init(&group->tg_joinsem, 0, 1);
#endif
#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
	(void)sem_init(&group->tg_exitsem, 0, 0);
#endif
	return OK;
}

/*****************************************************************************
 * Name: group_initialize
 *
 * Description:
 *   Add the task as the initial member of the group.  The full creation of
 *   the group of a two step process:  (1) First, this group structure is
 *   allocated by group_allocate() early in the task creation sequence, then
 *   (2) this function  is called to set up the initial group membership.
 *
 * Parameters:
 *   tcb - The tcb in need of the task group.
 *
 * Return Value:
 *   0 (OK) on success; a negated errno value on failure.
 *
 * Assumptions:
 *   Called during task creation in a safe context.  No special precautions
 *   are required here.
 *
 *****************************************************************************/

int group_initialize(FAR struct task_tcb_s *tcb)
{
	FAR struct task_group_s *group;
#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
	irqstate_t flags;
#endif

	DEBUGASSERT(tcb && tcb->cmn.group);
	group = tcb->cmn.group;

#ifdef HAVE_GROUP_MEMBERS
	/* Allocate space to hold GROUP_INITIAL_MEMBERS members of the group */

	group->tg_members = (FAR pid_t *)kmm_malloc(GROUP_INITIAL_MEMBERS * sizeof(pid_t));
	if (!group->tg_members) {
		kmm_free(group);
		return -ENOMEM;
	}

	/* Assign the PID of this new task as a member of the group. */

	group->tg_members[0] = tcb->cmn.pid;

	/* Initialize the non-zero elements of group structure and assign it to
	 * the tcb.
	 */

	group->tg_mxmembers = GROUP_INITIAL_MEMBERS;	/* Number of members in allocation */

#endif

#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
	/* Add the initialized entry to the list of groups */

	flags = enter_critical_section();
	group->flink = g_grouphead;
	g_grouphead = group;
	leave_critical_section(flags);

#endif
#if defined(CONFIG_PREFERENCE) && CONFIG_TASK_NAME_SIZE > 0
	/* The values of private preference are managed by task group.
	 * Set a name of task group, tg_name for private preference. */

	strncpy(group->tg_name, tcb->cmn.name, strlen(tcb->cmn.name) + 1);

#endif
	/* Save the ID of the main task within the group of threads.  This needed
	 * for things like SIGCHILD.  It ID is also saved in the TCB of the main
	 * task but is also retained in the group which may persist after the main
	 * task has exited.
	 */

#if !defined(CONFIG_DISABLE_PTHREAD) && defined(CONFIG_SCHED_HAVE_PARENT)
	group->tg_task = tcb->cmn.pid;
#endif
#if defined(CONFIG_SCHED_ATEXIT) && !defined(CONFIG_SCHED_ONEXIT)
	/* atexit support *********************************************************** */

	sq_init(&(group->tg_atexitfunc));
#endif

#ifdef CONFIG_SCHED_ONEXIT
	/* on_exit support ********************************************************** */

	sq_init(&(group->tg_onexitfunc));
#endif

	/* Mark that there is one member in the group, the main task */

	group->tg_nmembers = 1;
	return OK;
}

#endif							/* HAVE_TASK_GROUP */
